1. Field of the Invention
This invention relates to an elastic yarn winder for winding large-diameter elastic yarn packages onto a plurality of tubes without the elastic yarn crossing between the tubes and without broken yarn ends remaining in the inner layer ("core") portion of the elastic yarn package. This invention also relates to an elastic yarn transfer method for reliably transferring an incoming elastic yarn end from a full package to an empty tube.
2. Description of the Prior Art
Winders of the prior art are shown in FIGS. 4-6. These have hitherto been used for winding elastic yarns such as polyester, polyether, polyurethane and polyamide yarns, and for producing elastic yarn packages. The winder shown in FIG. 4 has, on a turnable table 15, a single spindle 11, a friction roll 12 that drives this spindle 11, a traverse mechanism 13 that traverses the yarn, and a traverse releasing mechanism 14 that removes the yarn from a traverse guide mounted in traverse mechanism 13. This winder is generally used for producing large-diameter elastic yarn packages having diameters up to 350 mm.
The above-mentioned turnable table 15 can turn only several degrees by hand about a rotating shaft. The single spindle 11 mentioned above is supported in a freely rotatable manner by the table 15, and a plurality of tubes 16 can be mounted on the spindle.
Friction roll 12 presses constantly against the layer of elastic yarn that has been taken up onto tube 16, and rotatably drives tube 16 in a clockwise direction.
A traverse guide (not shown) is provided on the above-described traverse mechanism 13. This traverse guide guides elastic yarn Y back-and-forth over the traverse range, so that traversing movement of the yarn is carried out. In addition, a plurality of yarn guides 19 are provided on top of traverse mechanism 13.
The prior art practices for taking up and transferring elastic yarn using the winder depicted in FIG. 4 are disclosed in FIG. 5, which is also of the prior art.
FIG. 5(1) shows the elastic yarn being taken up and a yarn package 18 being formed.
FIG. 5(2) shows that when elastic yarn package 18 has been fully wound, a plurality of continuously fed elastic yarns Y are drawn in by means of suction nozzle 20 on suction device 17, and separated from fully wound elastic yarn package 18. Table 15 is turned several degrees, thereby separating spindle 11 from the friction roll 12 and stopping rotation of the spindle. The fully wound elastic yarn package 18 mounted on the spindle 11 is then pulled off, following which an empty tube 16 is mounted in its place.
FIG. 5(3) shows first, the traverse releasing mechanism 14 being lowered so that the yarn is no longer traversing, and the spindle 11 on which an empty tube 16 has been replaced is once again pressed against the friction roll 12, thereby causing spindle 11 to rotate. Here, the plurality of elastic yarns Y that have been drawn in at the suction nozzle 20 are respectively grasped by a plurality of guides 19 provided at the top of traverse mechanism 13 and are drawn in by the suction device 17. This way, as indicated by the dashed line in the Figure, the elastic yarn Y passes between traverse mechanism 13 and friction roll 12. Afterwards, the suction nozzle 20 is rotated clockwise along the outer periphery of the single foremost empty tube 16 that has been mounted on spindle 11, thus winding the elastic yarn Y onto the single empty tube 16.
Elastic yarn Y, prior to entering the suction nozzle 20, is then forcibly stretched so that breakage of the elastic yarn occurs.
Next, the traverse releasing mechanism 14 that removes the elastic yarn Y from the traverse guide is returned to the original position, the elastic yarn Y is grasped by the traverse guide and traverse is begun, thereby completing the change in the elastic yarn Y.
These prior-art winders and method, however, have inherent disadvantages. When winding of the elastic yarn package 18 begins, as shown in FIG. 6 (also of the prior art), elastic yarn Y is first wound onto just the foremost hollow tube 16a that has been mounted on the spindle. Because the other elastic yarns Y (those not intended to be wound onto foremost tube 16a) have been grasped by guide 19 at the top of the traverse mechanism 13, the other elastic yarns Y are shifted to the positions of the respective empty tubes behind 16a by inertial force, at which positions they start being taken up onto their corresponding empty tubes 16. Therefore, during the interval between the beginning of take-up until the elastic yarn Y moves to the its proper corresponding tube 16 (by means of inertial force), the elastic yarn crosses between each of the tubes 16 further back and is taken up while passing each of the tubes.
When the packages are completed, at the time of yarn changing, the yarn is broken by forcible stretching of the elastic yarn and a contractile force acts upon the elastic yarn the moment that the yarn has broken. The direction of the contractile force of the elastic yarn Y becomes random and indeterminate, as a result of which the yarn end at which winding begins (the incoming cut end) can reach the traversing regions of the neighboring elastic yarn packages and become entangled in the neighboring tubes. The yarn end at which winding begins can also fly out from the sidewall of the fully or partially wound elastic yarn package and become entangled with other equipment.
Thus, utilizing prior art winders, elastic yarn can cross between each of the tubes at the initial winding stage (when the fully wound elastic yarn package is removed from the winder spindle) and the fully wound packages will be connected to each other by the crossed elastic yarn Y. In order to separate the packages, the crossing yarns must be cut. In addition, a further problem arises because the elastic yarns that crossed between each of the tubes are cut between the packages; that is, the pieces of yarn that have been cut remain at the interior of the foremost package.
As a result, yarn breakage will occur at users of common elastic yarn packages, resulting in reduced quality and commercial value of the elastic yarn. For these reasons, improved equipment and methods which avoid the creation of these cut ends have been long sought.
Japanese Registered Patent No. 9-2624345 (1997) discloses winders that produce elastic yarn packages having a relatively small (less than 170 mm) diameter. Here, because two spindles are provided on a turnable table and yarn transfer is carried out by turning of these two spindles, the yarn at the beginning of winding is not disposed so as to cross between the tubes. However, in this case, the diameter of the fully wound package is restricted by the distance between the spindle at the winding position and the spindle at the waiting position. This makes it difficult to produce large-diameter elastic yarn packages with winding diameters greater than approximately 250 mm. Therefore, either a winder having only one spindle needs to be used for the production of such packages or, alternatively, one must greatly widen the distance between the two spindles on an existing winder entailing enormous costs, comparable to the cost of producing a new winder.
Therefore, in prior-art winders and yarn transfer methods, there are limits on the efficient production of large-diameter elastic yarn packages which do not cause crossing of the elastic yarn between the individual tubes, leaving cut pieces of yarn in the interior layers of the package, and without letting the winding startup yarn ends fly off from the sidewalls of the elastic yarn package.